Pure ethanol has an octane of about 113. As you know, regular gasoline has an octane of 87, so it's a high-octane fuel. Race car drivers love using it. If you were talking about a flex-fuel vehicle where you could change the compression ratio and run on 85% ethanol, you could take advantage of that additional octane.
I should point out that I drove here in a flex-fuel vehicle today fuelled by 85% cellulosic ethanol. I've been driving on E85 since 2004.